Generally, a flow control device used to regulate the flow of fluid such as chemical solution or purified water used in manufacturing a semiconductor or the like includes a housing formed of a resin material such as a fluororesin which has superior chemical resistance so that the fluid flows in a flow passage provided to the flow control device.
However, the fluororesin being susceptible to thermal deformation such as thermal expansion would cause the housing to thermally expand or the like to undergo thermal deformation when the temperature of the fluid to be regulated changes in a short period of time or when there is a temperature change in the external environment. It is thus concerned that the thermal deformation would cause a seal surface forming the flow passage to be shifted more or less and a seal structure to be lost.
In order to suppress such thermal deformation, Patent Literature 1 discloses a form retaining means which is provided in a housing made of resin and is formed of a metal material undergoing less thermal deformation than the housing material.